Persistence of local populations of the Roman snail (Helix pomatia L.) for 15 years in conditions of moderate and constant anthropogenic impact – A case study from Central Europe

Abstract

The Roman snail (Helix pomatia L.) has been exploited for food to the point where it has been subject to legal restrictions on its collection, and steps have been taken to monitor its distribution and abundance. There are, however, few cases where monitoring has involved the precise re-examination of accurately located populations, and these have confirmed persistence over periods of up to six years. Using a standard methodology, ten populations of H. pomatia near the town of Września (central Poland) first surveyed in 1999 were re-sampled in 2014. In all cases the snail populations had persisted, and the habitats had not altered significantly. These results indicate that in the absence of over-exploitation or habitat change populations of this species persist. key words: Helix pomatia, local populations, monitoring, long-term observations The Roman snail (Helix pomatia L.) is one of the largest land snails in Europe. Although it has the most extensive range of any Helix species (welterschultes 2012, neuBert 2014), much of this distribution is a product of human introduction, as it has been exploited for food since Roman times, if not earlier (urBanski 1964, stePczak 1976, Bloszyk & kalinowski 2015). In recent times its popularity as food has led to over-collecting, especially in Western and Central Europe, including Poland (welch & Pollard 1975, radulescu & lustun 1980, wells & chatfield 1992, stePczak 1976). This over-exploitation coupled with some habitat destruction due to use of chemicals and machines for maintenance of urban green spaces (andreev 2006a, b, neuBert 2013) has reduced or eliminated many populations. Hence, the Roman snail was included in the IUCN Red List of Threatened Species (Lc category) (neuBert 2013), the European Red List of Non-marine Molluscs (cuttelod et al. 2011) and in Annex V of the EU Habitats Directive. The species is often farmed (williams 2009, neuBert 2013), but wild populations may still be harvested in some countries, including Poland. However, there are legal restrictions in place and national authorities have a duty to monitor populations of this species and ensure that such monitoring is effective in determining acceptable levels of exploitation (ligaszewski et al. 2014, Bloszyk & kalinowski 2015). In Poland, these restrictions and duties are laid out in the Regulation of the Minister of Environment dated 6 October 2014 (regulation 2014) on protecting animal species. In previous studies both published (Bloszyk et al. 2010, 2012, tworek & zaJąc 2012) and in reports (ryBak 2010, glowacka 2012, misa 2014) we have provided data on monitoring particular populations of Roman snails for 5–9 years, thus contributing to the legal requirements. Here, we report on the monitoring of 10 randomly chosen sites of 166 Jerzy Bloszyk, Krystyna Szybiak, Tomasz Kalinowski, Zofia Ksiązkiewicz-Parulska Fig. 1. Distribution of the studied sites near Września town (original numbering of sites provided by szmit 2000) Table 1. Description of the studied sites in 1999 and 2014 (original numbering of sites provided by szmit 2000) Site no. Area surface [m2] Vegetation (1999 and 2014) Human impact